8.6.17. MLinExpr¶

class MLinExpr¶

Represents a multidimensional array consisting of LinExprs. Generally, it is generated by arithmetic operations among constant, Var, MVar, MLinExpr or other types. For example:

# Multi-dimensional array variable plus a constant
mvar + 1
# product of variable and numpy array
var * numpy.ones((1, 1))

Properties

`ndim`	Number of MLinExpr dimensions
`shape`	Shape of the MLinExpr
`size`	Number of expressions contained in the MLinExpr

Methods

`clear()`	Perform the clear operation on all contained linear expressions, that is, all contained linear expressions become empty expressions
`copy()`	Return a copy of the MLinExpr
`getValue()`	After the problem is solved, the values of all linear expressions are returned
`item()`	Get the unique expression contained in the current MLinExpr
`sum()`	Sum all included expressions and return the summed result
`zeros()`	Return a MLinExpr of the specified shape, which contains empty expressions

clear()¶

Perform the clear operation on all contained linear expressions, that is, all contained linear expressions become empty expressions.

example:

mLinExpr.clear()
print(mLinExpr[0, 0].item().size() == 0)

copy()¶

Return a copy of the MLinExpr.

example:

another = mLinExpr.copy()

getValue()¶

After the problem is solved, the values of all linear expressions are returned.

example:

m.optimize()
print(mLinExpr.getValue()[0, 0])

item()¶

Get the unique expression contained in the current MLinExpr.

example:

mat = m.addMVar((2, 2))
mLinExpr = mat + 1
first = mLinExpr[0, 0]
print(type(first))
print(type(first.item()))

Note

An exception is thrown if the current MLinExpr contains more than one expression.

sum(axis=None)¶

Sum all included expressions and return the summed result.

Parameters: axis=None – Sum along the axis

example:

mat = m.addMVar((2, 2))
mLinExpr = mat +1
print(mLinExpr.sum().getConstant() == 4)

zeros(shape)¶

Return a MLinExpr of the specified shape, which contains empty expressions.

Parameters: shape – The shape to be specified.

example:

mLinExpr = MLinExpr.zeros((2, 2))
mLinExpr += x
print(mLinExpr[0, 0].item().size() == 1)